Numerical investigation of the effect of primary nozzle geometries on flow structure and ejector performance for optimal design

A numerical simulation of the internal flow structure of a steam ejector is conducted in a jet refrigeration system. The previous studies widely used traditional performance curves for assessment of ejector performance. However, a critical performance curve which is obtained by connecting each critical point at various generator temperatures has been rarely studied. In this paper, we design a range of primary nozzles with same or different area ratio by varying the nozzle’s throat and exit diameters, and the impact of nozzle geometries on the critical performance curve is mainly explored. Moreover, we proposed a linear fractional fitting function of generator temperature to predict the critical entrainment ratio and compression ratio for different nozzles. It is found that the nozzle throat diameter is a key parameter affecting the ejector performance and shock wave structure, and the hot source may provide some guidance for the adjustment of nozzle size.